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Great project, the flex actually let the sail respond much like an Eddy Kite was intended to fly, they did not have tight sails and depended on the billow for stability. But that's not what you're looking for in a controllable kite and contributed to the slow turning. 6mm and Fiberglass would be a bit soft for that size kite, hope the 8mm works out.

The sail looks great though, keep us posted on your progress,

I'm certainly curious on how the rudder will effect the kite compared to just varying the angle of the sail. The old Navy video I've seen didn't show the kite to be easily controllable or accurate enough for team flying but who knows if that pilot had more then 5 minutes practice. I suppose you could revert the framing and bridling to a TRLBY style with a free floating rudder for historical purposes but it would be great if they flew fine in proper trim.

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"Living is easy with eyes closed, misunderstanding all you see" John W Lennon

"People do not quit playing because they grow old, they grow old because they quit playing" George Bernard Shaw

Thanks for your kind words! I don't think I'll be able to get rid of all the billow, but a bit less should make the kite turn a bit better (at the cost of stability, but you don't want stability that much in this case). In hindsight, the 6mm was indeed a bit naive, but I haven't got much kite-building experience, so blame it on that (and I can always use the 6mm spars for something else again, so nothing lost and experience gained).

Trlby-type bridling is indeed an option, but I'm stubborn enough to try and make it fly with the original bridling and a functional rudder, if at all possible.

As to team-flying (or rather pair-flying), I don't expect it to be as steerable as a modern kite, so whatever pairs routine comes out in the end will depend on what the kites can and cannot do. We've got plenty of kites for modern routines, with sharp corners, quick turns, etc, so having a pair in our quiver which does 'something different' is only a good thing.

THis is a cool project. THe rudder system is going to be a challenge to get right. THe original ruder system was hinged wood 1/4-3/8 inch thick screwed to a flat spot in the rear of the spine with two tiller pieces to tie the lines to. Basically a scaled version of a real plane stabilizer. The challenge for you is to make it attach to the round frame rod and not move at all and get the vertical alignment right. Standard spar fittings won't work but you can use balsa wood and rc airplane flap hinges for the rudder materials or lexan instead of wood and make a door hinge type set up. I'll see what info I can find on the rudder system for you.

I kind of see some missed details though. THe original garber had a tension line in the edge of the sail run over notches in the spar edges and an adjustable bow line for the cross spar. I don't see these on your version and the sail billow leads me to think you don't have the line through the entire edge. YOu might also consider p-300 or p400 rods instead of 8mm. Using split nocks and a leech line set up might yeild a more accurate recreation of the build and flight and allow for easy integration of a bow line.

Just saw your edit: yes, there is a tension/leech line running through the edge of the entire sail, which runs through split nocks at the four spar ends. I will need to play with the amount of tension in the leech line. There is indeed no bow line for the cross spar (yet?), but that can easily be added if required.

My aim was not to make an accurate replica, as I would have needed to use wood for the frame, for instance, but to make an 'interpretation' using modern materials. So some details will be very close to original (such as the plane silhouettes), some details will be quite different. And once they're both ready and flying, I do think we might be the only kite team in the world flying a pair routine with 'target kites'

When you do add the rudder you will see why the bow line is there. Adjusting the bow tension along with how the ridder works changes how the kite responds. I had a chance to fly one years ago at a military history show and its a unique kite. When done right you can do tight immelman(more hammerhead stall really) style turns and even mimic death spiral flat spins but you have to be good with it. Think dog fight flying

As for the replica, using modern materials is fine but replicating the build techniques is where the performance will come from. That kite was designed to mimic as close as possible actual flight patterns and it does really well.

Bow line can be added very easily. From the plans I saw, and the original patent, my understanding of the (main) function of the bow line was to force the flat frame into a dihedral. My kites' frames already have that as I used a dihedral cross piece. Once the rudder is added, I will fly the kites with and without bow line, and see whether it makes a difference.

Cloth Hinges on the rudder rather then hardware to keep the weight down, we used them on the old fly by wire model airplanes and they should work fine on your project.

I would possibly look at using a molded dihidral and a two piece spreader. Then you could epoxy the dihidral to the spine and custom build an "L" shaped fitting for the rudder rod off the spine (also epoxied to the spine at a 90* angle to the dihidral) using the moldable plastics referenced here http://www.gwtwforum.com/index.php?topic=9030.0 Should be able to make the rudder easily removable that way for transportation.

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"Living is easy with eyes closed, misunderstanding all you see" John W Lennon

"People do not quit playing because they grow old, they grow old because they quit playing" George Bernard Shaw

I would possibly look at using a molded dihidral and a two piece spreader

That's exactly what I have; sorry if I didn't make that clear! And I am indeed thinking about some sort of 'cloth hinge' for the rudder. Much easier to implement, lighter (as you say) and there is very little force on the hinge, so it should be fine.

Yeah I studied your pics and video closer and saw you had a Dihedral in there. So I guess my point is that gluing the dihedral and rudder mounts to the spine should keep the rudder properly aligned. Seeing that the tail is actually quite long with a short rudder (I was picturing the original having a short stationary surface with large moveable surface) it shouldn't be too difficult to design a mounting system for the rudder on your new 8mm spine. It currently appears to fly very similar to the one in the WWII video using the TRLBY style steering, if the original type rudder control proves daunting I can see just adding a dummy rudder as a possible alternative.

Nice work on the website too,

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"Living is easy with eyes closed, misunderstanding all you see" John W Lennon

"People do not quit playing because they grow old, they grow old because they quit playing" George Bernard Shaw

I would possibly look at using a molded dihidral and a two piece spreader

That's exactly what I have; sorry if I didn't make that clear! And I am indeed thinking about some sort of 'cloth hinge' for the rudder. Much easier to implement, lighter (as you say) and there is very little force on the hinge, so it should be fine.

THe rc air plane aileron hinges are mylar with a fiberglass mat coating that you superglue into slits cut into the material. simple yet very strong and effective. From what I can find out the rudder is roughly 15% of the spine split 70/30 and 5 inches tall (almost scale to the silouette). A dummy rudder won't work as you will lose a lot of turn. as for mounting hardware, if you groove the base to fit the rod (concave the edge to the rod diameter) just poke some holes in the rudder and use some small zip ties to hold it on with cut end cap pieces under the ties to prevent slipping and rotating.

Hmm you say your rudder has no noticable effect. I would say the dimensions and angle are wrong then. The original kites were designed to be able to mimic tight immelman style turns (wingovers). It looks like your close in performance so just a inch or so to the rudder dimensions should get you there. The original rudders were 6 inches tall 9 inches long total. 6x5 moveable rudder surface as far as i can find out. Nice work though and I look forward to seeing your pairs routine.

The wind was quite light today; maybe with more wind, and more kite speed, I will notice an effect? Flying the kite didn't really feel different to me today, compared to when I flew the other one without rudder a few weeks ago. Time will tell!

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